The invention relates to a circuit arrangement for telecommunication installations, including telephone exchange installations, in which individual devices are activated by a central switching device with device-specific connect commands transmittable by the latter to the equipment, and in which, after selecting and connecting the particular device to the switching device, between these two information for ensuring correct connect command transmission to the device as well as for ascertaining of the connection having thereupon been established with the correct device is exchanged, and in which different commands transmitted by the switching device to a connected device are checked command-specifically through acknowledgement signals transmitted back, and in which from the switching device to the particular device after completed connection a start command is transmitted and before or for disconnection, a stop command is transmitted.
The publication "telcom report", 5 (1982) No. 4 (English language edition) pp. 262 describes a circuit arrangement for telecommunications systems, in particular telephone exchange installations, in which individual devices are activated by a central switching network, in that the latter causes an activating device through an address transmitted to the activating device to transmit activation data to a particular device over an activation circuit between it and the activation circuit, with the different devices being activatable over different or partially different activation circuits, and in which through the activation data connecting means in the particular individual device are caused to connect the latter with a common bus line leading to the central switching network. The activation device mentioned in it consists in this known case of a module processor (SLMCP), which is provided for a multiple subscriber connecting circuit (SIM). One such activation device shown in the lower illustration on page 263 of this publication, receives in each instance for the activation of one single individual device (single subscriber connecting circuit SUC/COSLAC) one address from a central switching network (concentrator Processor DICC), by which this activation device is caused to transmit activation data across an activation circuit extending from it to the individual device. The different individual devices are activatable across different or partially different activation circuits. In each instance, therefore, a separate activation circuit, independent of all other activation circuits, can run from the activation device to each of the discrete devices. The activation circuits can, however, also be provided partially in common for the different discrete devices. In this case, the different individual devices have only partially different activation circuits. One such arrangement is shown, for example, in the German Patent No. 1 562 230. In it, a coordinate activation of discrete devices through an activation device is disclosed. In this case, the connecting means are electromagnetic relays with connecting contacts. The connecting means, however, can equally well be realized through switching means functioning purely electronically. As is further apparent in the mentioned illustration on page 263, the connecting means serve to connect an individual device due to its activation with a common bus line leading to the central switching network.
The activation of individual devices, can thus take place across device-specific discrete activation circuits or across partially common activiation circuits, as described in the above mentioned German Patent No. 1 562 230 (activation in two coordinates) or also in encoded form, with different codes being applicable, for example, the decimal code or other codes.
The usefulness of an activatable activation device encoded through addresses, which is provided for each of a small number of individual devices and activates each of them across entirely or partially device-specific activation circuits, resides in that the number of the circuits leading from a central switching network can be kept relatively low. When activating individual devices, however, the problem also exists of surveillance of the activation and connection processes taking place faultlessly. If the coded activation addresses transmitted by a central switching network reach the individual devices to be activated, the possibility exists to monitor the correctness of the address transmission by transmitting back the particular received address or the complement of a particular received address or to monitor continuously by activation through address and its complement. Other surveillance possibilities exist, for example, those stated in the already mentioned German patent, with the assumption that the activation circuit lead directly from the central switching network, which runs the activation and connection processes.
From the German Patent (examined) No. 35 12 846 another surveillance method regarding the correct running of the activation and connection processes is known. In it, when activating an individual device in connection with data transmission processes from a central switching device to the individual device, a device-specific indentification marker is transmitted across the particular bus line to this individual device, which is stored here. Each time an individual device is activated by the central switching device, the identification transmitted with it is compared to the identification already stored in the individual device. This comparison can take place in the individual device. Likewise, the possibility also exists of transmitting the identification stored in the individual device to the central switching device and comparing it here with the previously transmitted identification. In both cases this known arrangement requires, that in each of the individual devices activatable by the central switching device an identification is stored, and, in particular, in each instance from one activation process to the next. The individual devices, therefore, must be in a position to store such identifications.